This invention generally relates to mattresses and mattress coverlets for preventing, reducing, and/or treating decubitus ulcers, also known as pressure sores or bedsores. More particularly, this invention concerns therapeutic mattresses or mattress coverlets capable of transferring or dissipating moisture vapor and heat from a patient""s skin.
Often, patients that are bedridden or immobile can develop decubitus ulcers (pressure sores or bedsores). Such ulcers are often caused by pressure, friction, shear, moisture, and heat. Pressure results in a reduction of blood flow to the soft tissues of the body, particularly the skin. Continuous lack of blood flow, and the resultant lack of oxygen, can cause the skin to die and ulcers or sores to form. Friction and shear of the skin against the support surface can lead to skin tears and decubitus ulcers. Moisture and heat may lead to skin maceration. Other factors play a part in determining the speed with which such ulcers will form or heal including the overall health of the patient and such patient""s nutritional status.
To insure normal (or, at least, relatively improved) blood flow to such areas of potentially problematic contact, patients are often turned or repositioned regularly by medical personnel. Turning or repositioning of patients, however, is not always possible, particularly where trained medical staff are not available. Additionally, repositioning can be painful and disruptive for the patient. In an effort to overcome such difficulties, numerous mattresses and mattress coverlets have been developed to more evenly distribute, across the patient""s skin, the pressure generated by the weight of the body. At least two methods have been used to redistribute skin pressure. The first is the use of static supports such as foam, air or water mattresses. The second method involves the use of alternating pressure inflatable mattresses or mattress coverlets that dynamically shift the location of support under the patient. Two examples of alternating pressure inflatable surfaces are illustrated in U.S. Pat. Nos. 5,509,155 and 5,926,884, the disclosures of which are fully incorporated herein by reference.
In addition to such two methods of redistribution of skin pressure, an additional feature has been utilized to help address other of the aforementioned factors important to the healing process. In particular, a low air loss feature has been used to aid in the removal of both moisture vapor and heat thereby reducing both at the patient-bed boundary. This has been done in an effort to prevent skin maceration, keep wounds dry and to promote healing.
There have been essentially three approaches to achieving a low air loss support surface. First, relatively tiny holes can be provided in the top surface of inflatable air cells of an air mattress having a vapor-permeable top surface. Such holes allow extra air to circulate inside the mattress to assist in drying moisture vapor passing through the top surface from the patient.
Second, relatively tiny holes can be provided in the top surface of the mattress so that the air venting from the air cells can transfer through the top surface to the patient in order to remove both heat and moisture from the area immediately surrounding the patient.
Finally, a multi-layer mattress coverlet can be used wherein the top layer is perforated to allow air flowing between the top layer and a middle vapor-permeable layer to exhaust across the patient thus aiding in removing both moisture and heat from the area immediately surrounding the patient. The third layer of such a three-layer approach may be a three-dimensional fabric, which allows for additional moisture vapor to be carried away from the patient.
While each of these approaches is useful for its purpose, there are various disadvantages with these approaches and in particular, with using them individually. The first and second referenced approaches to obtaining a low air loss feature requires a large compressor pump to maintain sufficient air to inflate the air cells of the mattress. Such large compressor pumps tend to be very noisy, require high electrical consumption and generate significant heat in a relatively confined area. Such high electrical consumption, and the additional need for continuous blower operation, has, in the past, resulted in over-heating of the air used to circulate about the patient. Conversely, in the case of an elderly patient, airflow directly across their body could result in an uncomfortable reduction in body temperature or even a drying out of the skin beyond that which is helpful.
Additionally, having holes in air cells of an inflatable air system results in a support surface that will deflate if there is a loss of electrical power or if no such power supply is available. Further, having perforations in the patient-bed contact surface results in a mattress that is not fluid-proof. This allows for potential contamination of the interior of such mattress by bodily fluids, products used to treat the patient and/or products used to clean such mattress itself. All three referenced approaches fail to allow air to flow under load (i.e., underneath the patient or through the top surface to the patient""s skin when supporting the weight of the patient).
Similarly, some prior art mattresses and mattress coverlets have had difficulty in controlling billowing. Billowing is the uncontrolled inflation of the upper surface of a mattress or mattress coverlet in the area immediately surrounding the outline of a patient""s body when the patient lies on the mattress. In essence, the mattress or mattress coverlet fails to fully support a patient and instead seemingly envelops them when the patient""s weight is applied thereto. Thus further illustrating the failure of some prior mattresses and/or mattress coverlets to fully support the patient and thus resulting in the air flow through the mattress, mattress top layer, or through the coverlet (i.e., the three aforementioned approaches) to flow around the patient, rather than flowing underneath the patient to aid in controlling moisture and heat.
With all of the above approaches, it is further unknown to have the capability to turn on or off the low air loss option while retaining through the use of powered air cells the redistribution of skin pressure feature of the mattresses or mattress coverlets. If a low air loss therapy is not desired, a different system must be utilized with an alternative controller and air cell array.
The present invention recognizes and addresses various of the foregoing limitations and drawbacks, and others, concerning the prevention and/or treatment of decubitus ulcers. It is, therefore, a principle object of the subject invention to provide an improved mattress and/or mattress coverlet for use in the prevention and treatment of decubitus ulcers. More particularly, it is a principle object of the subject invention to provide a mattress and/or mattress coverlet incorporating an air circulation system that does not exhaust its air directly across the patient.
Another more particular object of the subject invention is to provide a new air flotation mattress and/or mattress coverlet including a low air loss feature. In such context, it is a further object to provide a mattress and/or mattress coverlet wherein the low air loss feature can be turned on or off as desired for the treatment of the patient, independently of how the basic patient support surface is operated.
It is still a further object of the present invention to provide a mattress and/or mattress coverlet including a three-dimensional non-crush fabric to allow for the airflow of such a low air loss feature to flow under load.
Another general object of the subject invention is to provide a mattress capable of selectively providing either an alternating pressure inflatable support or a floatation support for the redistribution of skin pressure.
It is still a further object of the subject invention to provide a self contained external control system (ECS) including at least two pumps which are required to respectively maintain both the inflation of the mattress support and, if desired, the low air loss feature of the mattress coverlet. In such context, it is a further object of the present invention to provide a mattress or mattress coverlet capable of maintaining inflation of the patient support surface during a loss or unavailability of electrical power.
Another object of the present invention is to provide an independently usable low air loss coverlet, which may be combined with various support scenarios, such as with preexisting mattress support systems, patient positioners, and/or wheelchair/seating cushions (as a retrofit or as original equipment combined with a prior design), regardless of whether such prior systems incorporate an air powered patient support surface.
Additional objects and advantages of the invention are set forth in, or will be apparent to those with ordinary skill in the art from the detailed description herein. Also, it should be further appreciated that modifications and variation to the specifically illustrated, referenced, and discussed features, materials, or devices hereof may be practiced in various uses and embodiments of this invention without departing from the spirit and scope thereof, by virtue of present reference thereto. Such variations may include, but are not limited to, substitution of equivalent materials, means, or features for those shown, referenced or discussed, and the functional, operational, or positional reversal of various features, parts or the like.
Still further, it is to be understood that different embodiments, as well as different presently preferred embodiments, of this invention may include various combinations or configurations of presently disclosed features, or elements, or their equivalents (including combinations of features or configurations thereof not expressly shown in the figures or stated in the detailed description).
One exemplary embodiment of the present invention includes an air flotation mattress with an ECS. The support surface of such air flotation mattress may include a foam shell with a surface treatment on its upper surface. An exemplary GEO-MATT(copyright) surface treatment is illustrated in commonly owned U.S. Pat. No. 4,862,538, which is fully incorporated herein by reference. Such surface treatment aids in redistributing skin pressure. Additionally, the air floatation mattress includes a plurality of air cells running side-to-side providing the ability to sub-divide the mattress support into pre-designated zones.
Included with such an exemplary air flotation mattress may be a low air loss coverlet in accordance with the subject invention. Such air flotation mattress serves as the primary support surface offering both a flotation and alternating pressure treatment option. Such low air loss coverlet provides an option to enhance the process of removing moist warm air from the area around the skin of the patient. It achieves such function by employing a patient-contact fabric top layer possessing a high moisture vapor transfer ratio enhanced by airflow through an inner layer of the coverlet.
Such a mattress coverlet preferably comprises three layers. The first layer (on the top, facing the patient interface) is a vapor permeable layer, which allows moisture vapor and heat to travel away from the patient""s body. Such moisture vapor enters the second layer, which may comprise a non-crush three-dimensional fabric, such as a specialty knit. The ECS forces air through the second (i.e., middle) layer to aid in carrying away the warm moist air. The final layer of such mattress coverlet (furthest from the patient interface) is a waterproof, vapor impermeable layer that acts as a boundary to protect the underlying mattress.
The mattress coverlet""s third layer may additionally comprise a coverlet-mattress topper such as a zippered sheath for encasing a mattress. Such construction advantageously enables the coverlet to effectively function with any mattress and not just the air flotation mattress as disclosed herein. Accordingly, various embodiments of the subject invention may comprise a mattress coverlet in accordance with the subject invention, combined with a variety of underlying patient support surfaces, including a mattress, patient positioner, and/or wheelchair/seating cushion (regardless of whether pre-existing, disclosed herewith, or later developed).
Yet another exemplary embodiment of the present invention includes an air flotation mattress with an ECS. The air floatation mattress includes a plurality of air cells running head-to-foot. A foam shell topper with foam bolsters and foam sides running the length of the mattress on either side forms the air flotation mattress. At each end of the air flotation mattress and capping the foam bolsters and sides is either a foam header or foam footer, which along with the bolsters form a cavity in the mattress. This cavity is for positioning of the air cells.
Included with such an exemplary air flotation mattress may be a low air loss coverlet in accordance with the subject invention. Such air flotation mattress serves as the primary patient support surface. Such low air loss coverlet provides an option to enhance the process of removing moist warm air from the area around the skin of the patient. It achieves such function by employing a patient-contact fabric top layer possessing a high moisture vapor transfer ratio enhanced by airflow through an inner layer of the coverlet.
Such a mattress coverlet preferably comprises two layers. The first layer (on the top, facing the patient interface) is a vapor permeable layer, which allows moisture vapor and heat to travel away from the patient""s body. Such moisture vapor enters the second layer, which may comprise a non-crush three-dimensional fabric. The ECS forces air through the second layer of such mattress coverlet to aid in carrying away the warm moist air.
The air floatation mattress additionally comprises a multi-layer mattress topper comprising three layers. The first layer of such multi-layer mattress topper (adjacent such a mattress coverlet) is a waterproof, vapor impermeable layer that performs as a boundary to protect the underlying mattress. The second layer may comprise a non-crush three-dimensional fabric. The ECS forces air through the second (i.e., middle) layer in addition to providing airflow through the second layer of such a companion low air loss mattress coverlet.
The multi-layer mattress topper""s third layer may comprise a waterproof, vapor impermeable layer that performs as a boundary to protect the underlying mattress. The topper""s third layer serves as the basis for a zippered sheath for encasing such a foam-based portion of the mattress. The multi-layer mattress topper""s first and third layers are welded around their perimeter so as to secure their construction.
Similarly, the two layers of such a coverlet are sewn together around their perimeter and may utilize an elasticized band there-around for securing the coverlet to the mattress. Such construction advantageously enables the coverlet to effectively function with any mattress and not just the air flotation mattress as disclosed herein. Accordingly, various embodiments of the subject invention may comprise a mattress coverlet in accordance with the subject invention, combined with a variety of underlying patient support surfaces, including a mattress, patient positioner, and/or wheelchair/seating cushion (regardless of whether pre-existing, disclosed herewith, or later developed).